1. Field
Example embodiments relate to a semiconductor device and a method of manufacturing the same, for example, to a semiconductor device having an on-chip type electrostatic discharge (ESD) protection circuit and a method of manufacturing the same.
2. Description of the Related Art
Modern technologies allow computer peripheral devices to be more frequently used. Some computer peripheral devices, for example, electronic communication apparatuses (e.g., Bluetooth) and computer external memory devices (e.g., a flash memory), have high data transfer speeds and various operating voltage ranges. The integrated circuit inside these devices are frequently connected or disconnected to a computer system through external ports. An integrated circuit (IC) directly connected to an external port may receive an unrecoverable damage such as joining failure, contact damage, insulation breakdown, short or opening of a fuse etc. due to an electrostatic discharge (ESD) that flows into the external port. The ESD may be caused by various reasons, for example, inappropriate handling of the IC and inappropriate environmental conditions, such as abnormal operating conditions, and a poor printed circuit board of the IC.
With the development of semiconductor manufacturing process techniques, integration density of ICs is increased, and as a result, pads for signal input/output, line width, or thickness of deposited thin films are reduced. Accordingly, a tolerable current of ICs is also reduced, and thus, ICs are becoming more susceptible to ESD damage.
In order to prevent ICs from being damaged by the ESD, generally an ESD protection circuit is installed between a power source terminal VDD and a ground terminal VSS or an input terminal and an output terminal of an IC. The ESD protection circuit protects the IC by blocking an ESD current from flowing through the IC or by bypassing the ESD current.
Circuits in which zenor diodes, metal oxide varistors (MOVs), or silicon controlled rectifiers (SCRs) are included are conventionally used as the ESD protection circuits. However, these ESD protection circuits do not sufficiently respond to the reduction of tolerance current caused by the increased integration density of the ICs. For example, an ESD protection circuit may not be triggered by a relative small ESD surge, which is no longer safe to more sensitive and/or densely integrated ICs. Also, since the turn-on speed of the ESD protection circuits is slow, the ESD protection circuits themselves may be damaged by an ESD surge.
With the increase in integration density of ICs, there is a need to develop an ESD protection circuit that can respond to various ranges of ESD surges with a quick turn-on response.